Analysis and detection of biological molecules typically involve placing a sample onto an immobilizing membrane and then performing steps to detect the presence of or quantitate one or more particular biological molecules in the sample. A sample may be spotted directly onto the immobilizing membrane or transferred from a matrix to the immobilizing membrane by blotting. Such a transfer may be necessary because the matrix can be unsuited for many of the biological or chemical assays known to those skilled in the art. The transfer may be passive or energy-driven, such as by an electric current. Once the sample has been transferred to the membrane, the desired assay can be performed on the immobilized sample.
Methods of transferring biological molecules to immobilizing membranes are known in the art. For example, polynucleotide sequences may be transferred from a gel made of agarose or polyacrylamnide to a cellulose-derived or nylon membrane. Similarly, proteins may be transferred from an SDS-polyacrylamide gel to a cellulose-derived or nylon membrane. Immobilizing membranes made from nylon or cellulose-derived materials are porous and permit the transfer of polynucleotides or proteins through a variety of processes, some of which are energy independent and some of which, such as electroblotting, are energy-driven.
Many assays performed on biological molecules can be performed on a miniaturized scale. Many of these assays use samples and reagents that oftentimes are expensive or difficult to obtain. Accordingly, assays performed on a miniaturized scale are desirable because they may dramatically reduce the amount of sample and reagents required for performing the assay. Miniaturized assays are especially desired when an expensive or limited sample can be concentrated, thereby reducing the amount of the sample required for the assay while simultaneously increasing the sensitivity, accuracy or efficiency of the assay. In addition to the reduction of volume, miniaturization allows hundreds or thousands of assays to be performed simultaneously.
Some assays may include electrical manipulation of one or more samples, e.g., excitation of a sample to generate a desired visible signal, selective heating of particular samples, controlled transport of a fluid sample, and the like.
A heat-shrinkable film such as that reported in International Publication No. WO 99/53319, published Oct. 21, 1999, permits samples to be concentrated for miniaturized assays. Such a film may be used, for example, as a substrate to which reactants, e.g., peptides or nucleotides, may be affixed, thereby forming a riniaturized array. What is needed is an article including a shrinkable film that can be used to efficiently immobilize molecules transferred to the laminate for subsequent detection or assay. There is a further need that the article include an electrically conductive surface.